Apparatus for clamping a copy board on the base plate of a photographic enlarging apparatus



July 10, 1951 E. SCHREIBER 2,560,190

APPARATUS FOR CLAMPING A COPY BOARD ON THE BASE PLATE OF A PHOTOGRAPHIC ENLARGING APPARATUS Filed Oct. 14, 1950 j f M 2 IN V EN TOR.

Patented July 10, 1951 APPARATUS FOR CLAMPING A COPY BOARD ON THE BASE PLATE OF A PHOTOGRAPHIC ENLARGING APPARATUS Eduard Schreiber, Wetzlar, Germany, assignor to Ernst Leitz, G. in. b. H., Wetzlar, Germany, a

corporation of Germany Application October 14, 1950, Serial No. 190,074 In Germany March 13, 1950 4 Claims.

which the parts have been clamped by a tensioning member carried on the base plate as well as on the copy board which, b the actuation of a catch or handle, in some cases accompanied by spring action, clamped the parts together. In the prior apparatus the tensioning means itself was placed in the base plate while the copy board carried a guiding roove to receive a sliding member serving as the tightening member. The actuating grip for the clamping was in any case in the base plate. This type of apparatus required two catches for the mounting of the copy board on the base plate. Moreover, the tensioning member standin up from the plane of the base plate was a hindrance to the application of other copy boards not provided with a guiding groove to receive the tension member.

My invention obviates these disadvantages in the kinematic transformations of the tension device by mounting the tensioning member freely movable alon a guiding rail arranged parallel to, and within, the copy board and subject to the action of springs. The gripping member grips by means of a guiding head in an undercut guiding groove set into the base plate.

In a preferred embodiment of the invention the rail carrying the gripping member is hung on links within the hollow copy board and is drawn inwardly by springs. At the same time the guide rail can be clipped to the side wall of the hollow copy board by means of a projection, band, collar, etc. it projects through a corresponding openin in the side wall of the copy board to contact with an eccentric lever mounted on the side wall of the copy board. The gripping member itself is preferably supported on the rail by means of idler rolls and carries a stem with a cylindrical band of greater diameter with which it grips the undercut guide groove set in the base plate. The range of swinging of the rail hangers and the height of the hollow copy board are sufficient to permit the gripping member to be drawn by the springs completely into the copy board.

Through the above invention all actuating elements of the gripping device are brought within the copy board and can be actuated by a single handle which at the same time serves as a handle for positioning the copy board on the base plate.

The various features of the invention are illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a vertical section of a copy board and ground or base plate of a photographic enlarging apparatus provided with the gripping device of my invention, and

Fig. 2 is a bottom plan of the copy board of Fig. 1.

Referring to the accompanying drawings, a base plate of a pho tographic enlarging apparatus is provided in the usual manner with a supporting post 2. It also has an inset, undercut, guide groove 3. On the base plate a copy board 4 is slidably arranged. It comprises a box-like hollow body, open on one side, with the open side placed on the base plate I. On its upper side it carries a replaceable border mask 5. Within the copy board 4 a guide rail I is hung on links 6. Springs 8 acting on the parallelogram 6, I, 6 thus formed strive to draw the guide rail 1 into the interior of the copy board. A peg 9 extending from the guide rail I projects through an opening II] in the side wall II of the copy board. An eccentric lever I2 mounted on the side wall of the copy board 4 extends into the path of movement of the peg 9 so that by swingin the eccentric lever the rail 1 can be shifted lengthwise. The actuating lift of the lever I2 on one side and an enlargement I3 of the rail on the other side limit the movement of the guide rail 1.

The guide rail 7 carries a grip member I5 freely movable lengthwise of the rail on rolls I4. The grip member I5 carries a cylindrical peg I6 with a cylindrical ring I! of greater diameter extending into th undercut guide groove of the base plate I. The arrangement of the guide groove in the base plate I and the guid rail 1 in the copy board 4 is so selected that their lengths in normal positions of use are at right angles. However it is possible to turn the copy board 4 about the grip member I 5. The copy board 4 can be slid to any desired position on the base plate and gripped to the base plate.

The manner of using the apparatus is as follows:

In mounting the copy board on the base plate I, the grip member I5 is depressed by means of the eccentric lever I2, placed into an enlargement I-8 of the recessed guide groove 3 and moved into the guide groove 3, thereby uniting the copy board to the base plate. Upon releasing the cocentric lever I2 the springs 8 draw the guide rail into the interior of the copy board and, through the grip member I 5, grips the copy board 4 to the base plate. The grip may be released at any time by depressing the eccentric lever I2.

The invention contemplates that the apparatus can also be made without the addition of the eccentric lever l2. In this case the tension springs 8 continuously clamp the copy board 4 to the base plate by means of the grip member 15, so that a sliding of one relative to the other is possible by overcoming the gripping force. This gripping force will be so adjusted that the shifting of the copy board relative to the base plate I may be obtained by gentle pressure but a shifting of the copy board is not caused by use of the paper holder or border mask 5.

Having described my invention, what I claim is;

1. A copy board mounting for photographic enlarging apparatus which comprises a base plate having an undercut groove in its upper surface, a hollow copy board on said base plate, a guide rail within said copy board, said copy board being open below said guide rail, a grip member mounted on and slidable along said guide rail and having a gripping head extending into said undercut groove to engage said groove when drawn upwardly, and tensioning means comprising swinging links to support said rail and a spring to swing said links to upward position to draw said guide rail and grip member upwardly.

4 and having a gripping head extending into said undercut groove to engage said groove when drawn upwardly and tensioning means comprising swinging links to support said rail and. a spring to swing said links to upward position to draw said guide rail and grip member upwardly.

3. A copy board mounting for photographic enlarging apparatus which comprises a base plate having an undercut groove in its upper surface, a hollow copy board on said base plate, a guide rail within said copy board, said copy board being open below said guide rail, a grip member provided with guide and supporting rolls running on said rail and slidable along said guide rail and having a gripping head comprising a cylindrical stem extending into said groove and a cylindrical enlargement extending into the undercut part of said groove to engage said groove when withdrawn upwardly and tensioning means to draw said guide rail and grip member upwardly.

4. The copy board of claim 1 in which the guide rail movement and the dimension of the gripping head are such that the head may be drawn completely within the copy board.

EDUARD SCHREIBER.

REFERENCES CITED FOREIGN PATENTS Country Date Germany Sept. 7, 1935 Number 

